Automatic flat - bottom countersinking attachment for milling machines



Sept. 19, 1944. v p L Y 2,358,741

AUTOMATIC FLAT-BOTTOM COUNTERSINKING ATTACHMENT FOR MILLING MACHINES Filed Sept. 11, 1942 3 Sheets-Sheet 1 FIG.- 1.

INVENTOR.

1= ET ET 5h Eih ATTORN EYS.

Sept. 19 1944. A v p SHELBY AUTOMATIC FLAT-BOTTOM COUNTERSINKING ATTACHMENT FOR MILLING MACHINES Filed Sept. 11, 1942 5 Sheets-Sheet 2 F IG. 3.

' 'INVENTOR.

" I Pa"tar' fi'he'l't g- ATTORNEYS.

Sept. 19, 1944. P. SHELBY 2,358,741 AUTOMATIC FLAT-BOTTOM COUNTERSINKING ATTACHMENT FOR MILLING MACHINES Filed Sept. 11, 1942 Y s Sheets-Sheet s 2 23 .r 9/ 56. 3 i 6. T? 1; 5

- a4 93 1 2g 25- I 76 29-" 2 k 45 1 I '67 Ill -53 44 [I 29 I 3o 30 -22 25 v V -5 J0 F l-G. 12.

- 7/ 70 7 72 INVENTOR.

PETE? 5h E1135 Patented Sept. 19, 1944 UNITED STATES PATENT, OFFICE,

AUTOMATIC FLAT BoTToM COUNTER. SINKING1 ATTACHMENT FQR MILLING MAC HINES ,Peter Shelby, Fenton, Mich. Application september 11, 1942, Serial No. 457,998

4 Claims.

This invention relates to mechanism for producing fiat-bottom 'countersinks in metal plates, blocks, etc., and is particularly well adapted for use as an attachment for milling machines, although not necessarily limited tosuch. I

Recently there is a'great need for countersinks in plates, blocks, etc. having a perfectly fiat bottom with no central recess oropening and these have been produced, in the past, by rotating the work with respectto a rotating cutter. Considerable skill and time is required to produce a countersink by such procedure. As an example, one use for such countersink is to receive a pad of rubber or other resilient material as backing for sheet material being punched, the countersink being in the die of the punching equipment. Any recesses or holesin the bottoms of the countersinks have a tendency to damage the resilient pad. There are of course other uses for countersinks of this nature 1 and the foregoing is given merely as an example to emphasize the importance of producing a flat-.-

bottom countersink.

The principal object of thelpresent invention is to provide a simple and efilcie'nt countersinkautomatic operation until the countersink is completed.

A further object of the invention is to provide such means as may be adjusted to operate quickly and efiiciently according to the characteristics of the work, that is, whether operating on hard metal'or. the softer metals or alloys.

A further object of theinvention is to provide such mechanism as may beapplie'd to various makes andmodelsof milling machines with out coupling any portion of the attachmentto the machine except to the usual spindle and chuck.

Another object of the invention is to provide a flat-bottom countersinking tool which may be easily manufactured and quickly dismembered for adjustment or repair.

A still further object of the invention is to providein a countersinking tool simple and emcient means for rigidly supporting and bracing the cutter or work engaging element.

Qther objects and advantages of the invention. will appear in the following detailed description of the preferred embodiment of my invention, taken, in'connection with the accom- Tvertically adjustable on the'column 2, as by oppanying drawings, forming a part of this specification, and in which drawings: Figure '1 is a side elevation of a suitable milling machine showing my attachment applied thereto and with a piece of work in place.

Figure 2 is a front elevation of the same.

' Figure,3 is a detailed sideelevationof the attachment.

Figure 4 is a viewpartly in elevation. and partly in vertical section longitudinally of the head 10f the attachment.

Figure 5 is a planfview.

end elevation of the attachment.

Figure 8 is a view partly in elevation and part-.

ly in vertical section transversely 'of the rot'at- Figure 9 is a,dismembered view of the cutter V and carrier partsv in perspective. 7

Figure 1 0 is a View partly in elevation and partly in verticalsection of an assembly of the cutter and'carrier differing from that shown inFigure i. r

Figure 1l is afragmentary view in-elevation 7 showing an arrangement for quickfeed of the cutter with respect, to i the, work.

Figure 12 is a dismembered view of a smaller,

the carrier, in perspece cutter; and. portion of tive. I I Figure 13 is, a perspective view showing a typical example of the work accomplishedfby the mechanism. V

In Figures: 1 to 11, inclusive, is shown'a-millingmac hine A, a piece of work B, and the j mechanism C constituting the preferredembodiment of my invention. In Figure 12 is showna tool holder part of,modified form.

The milling machine A "comprises a1 suitable base l4, aumaintvertical column 15, a knee l6 erating'jcrank .1 15a saddle l8 slidable toward .and'away from columntli on knee IS, a table 19 horizontally slidable on saddle l8 in a direc-'- tion at right angles to the motion of the saddle,

aspindle 20,.and a chuck2l. It will be-see'n that'the work B mounted'on'stable l9 canbe adjustedto any desired position within the lim its. of motion of theparts. As. the'above adjustment is practicallyuniversal in milling machines and in itself constitutes no part of the present invention; further details ofdesoription thereof are deemed'unnecessary.

tool carrier 24 in head 22, and an actuating deavic'e' 21 for operating means 26.-

In addition to'including the spindle or shank thrust, when the tool is in use.

vided with vertical openings 34, for the reception of bolts 35 used to secure it to guide block 29; a

vertical bore 36 accommodating a portion of shank 23; and, a counterbore 31 open to the lower face 33 for a disc 38 formed integral'with shank 23.

Some of the bolts 35 may pass thru disc or the element 6| is used, that is, with the lug 61 engaging the bottom 56 of body portion 43, beneath set screw 59. Such an arrangement provides good surface-to-surface contact between the tool 25 and element 6|, in the direction of However, in Figure the position of element 6| is shown re versed, an arrangement permitting the mechanism to be used in producing countersinks of greater diameter than the arrangement in Figure 4. This is an arrangement suitable for use also where the work is not in hard metal.

flange 38, as shown in Figure 8 to aid in securing shown in Figure 8 with its lower portion 44 open to the bottom of the block and its upperportion 45 closed by plate 28; and ashaft bearing 46 thru oneend of the block and abearing 41 thru the other end thereof. r

, Thevbearing 41 has a shaft receiving portion 48 and. a thrust portion 49 for a purpose to be subsequently set forth.

To facilitate assembly, thefbottom plates 30 are provided with vertical holes 50 for bolts 5|, the shanks of which are received'in screw threaded recesses j 52 open the bottom of block 29. These bottom plates ex'tend longitudinally of the lower portion 44 of slot43 andengage the lower portion of tool carrier 24. I

The bearings 46 and 41 are axially aligned and co-axial with the upper portion 45'of slot 43.

The carrier 24, in'the example shown, includes an elongate body portion 53 provided I with a longitudinal slot54'open at'its top 55 and bottom '56; an upstanding block '51 integral with body portion 53 and provided with a transverse screw threaded bore 58; and a set screwf59 received in an opening68 extendingthru one end of the body portion 53 and connnumcatingwith one end of slot 54. The'carrier 24 alsoipreferably includes a substantially Zshaped'fillerpiece and brace" 61 to partially fit in s1ot'54 ,.-for' cooperation with a suitable tool125having a work engaging portion 63 and a shank portion 64.

Th'eelement 6| hasan upper portion inthe nature of a lug" 65 engaging 'thetop of shank 64inslot 54; anintermediateportion '66 disposed partially in the slot 54: -and partially therebelow; and alower portion "in-the nature'of' a lug'61 engaging the bottom '56 of body portion 53. Thusthe lug 6! limits the upward movement of the filler piece and brace 6| *in slot 54 so the upper-portion of the? element 6| cannot impede travel 'of thefcarrier24 in the guide block 29. 'If desired, a recess68 may be provided in a face of intermediate portioni66 above lug Bl'for the reception of theinner end of set screw 59.

As shown more particularly in Figures 4 and 8,

the body portion 53 is of a'width andheight for sliding'fitin the lower portion 44gof slot 43, and

the upstandingblock 51 is accommodated in the upper p0rtion-45 of slot, with the bore 58 of block 51 co-axialwithbearings 46 and 41.

Figure shows the preferred manner in which In Figure 12 is shown a modified filler piece and brace 10 for use with a smaller tool H having a work-engaging portion 12 and a shank 13. This is substantially like element 6i except that below a top lug I4 is provided spaced flanges 15 on intermediate portion 16, providing a slot ll for smaller shank 13.

The means 26 for reciprocating the tool carrier 24 comprises a screw 18, including shaft portion 19 in bearing 46, a shaft portion 89 received by bearing portion 48, a relatively long screw threaded portion 8| extending thru bore 58; a flange 82 engaging thrust portion 49 of bearing '41; a wheel 83 rigid with shaft portion 88 adjacent flange 82; and, retaining means 84 at the outer end of bearing 46. The wheel 83 is preferably provided with teeth 85 for cooperation with actuating device 21. The means 84 may comprise a thrust washer 86, a bolt 81 co-axial with and in threaded engagement with shaft portion 19, and a lock washer 88.

' Upon rotation of wheel 83in a clockwise direction, looking at Figure 7, the tool 25 will be fed toward the axis of'shank 23, bringing into use the flange 82 and thrust portion 49 of bearing 41, since engagement of the cutter with the work has a tendency to move the tool carrier 24 away from the axis of shank23.

Within the limits of motion of the parts, the wheel 83 may be rotated about its axis in either direction, and as the head22 is rotated it will be noted that the wheel 83 bodily travels in a zone encircling the head. The preferred actuating device 21 for'operating means 26 comprises an arm 81 normally located in a plane parallel to this Zone and loosely mounted on shank 23, a rod secured to arm" 89 and engaging some stationary part of the machine, such as the column I5 thereof, and one or more pins 9| adjustably secured to arm 89 as by set screws 92. Each pin 9l'is used to impart a partial turn to wheel 83 by engaging atooth 85 thereof, as is obvious from Figures 7 and 11 of the drawings.

' being located near the middle portion of the arm. Ithas a sliding fit with the shank sothat the arm may be bodily moved away from the position shown in Figures 3, 4, 6 and '7, but normally arm 89 is inert, andin the example shown, rests upon a washer encircling shank 23 to space the arm from the upper face of top plate 28. One end portion of 'arm 89'has'a block provided with a transverse opening 96 for the reception of rod 99, which'may be held in the adjusted position by setscrew 91. The other end portion of arm 89 is provided witha series of vertical openings 98 for the reception of pins 9|, the set screws 92 being used in the well known manner, torhold these pins in the desired adjusted position. The series of openings 98 are along an arc concentric with opening 93 'and are located so that a single pin'9l, as shown in Figure "I, may be adjusted in one of the openings 98 so as to normally project in the zone surrounding head 22 in which wheel 83 moves during use of the attachment, and so as to engage a tooth 85 of the wheel and impart partial rotation thereto. Or, two or more of the pins 9| may be used, as shown in Figure 11, where the work is soft, so as to obtain a greater speed ratio of a step-by-step nature between the tool carrier 24 and the spindle 28 for each revolution of the head 22. i

As a typical example of operation of the mechanism, assuming that the piece of work B has been secured to table l9 in any suitable manner and is free of the cutter or tool 25, the actuating device 21 may be lifted and held so that its pin or pins 9| are out of the zone of travel c of wheel 83 until movement imparted to spindle 20, and raising of the knee [6 will cut a circum ferential groove in the work, of the desired depth, as shown in Figure 6, whereupon the actuating device 21 may be lowered so as to function in automatically feeding the tool 25 toward the axialcenter of shank 23. From then on operation may be automatic. Instead of lifting the actuating device 2'! .as just described, it may be permitted to rest inert on washer 94, and by I manipulation of set screw 92, any pin 9! in the circumferential zone of travel of Wheel 83 may first be lifted so as to not actuate the wheel until the initial out has been produced, whereupon the desired pin or pins 9| may be lowered for automatic operation.

In Figure l I have shown a tubular rod 99 on rod 99,-an expedient which may be used if the stationary part of the milling or other machine, such as the vertical column I5 is spaced a considerable distance from chuck 2|.

It is to be noted that, according to the preferred form of my invention, the only element of the attachment, secured to the milling machine, is the shank 23, for while the actuating device 2'! is normally inert and held against movement by rod 90 or rod 99 engaging some stationary part of the machine, it may nevertheless be lifted to quickly prevent feed of tool 25, and to facilitate the initial cut shown in Fig ure 6.

As it may be noted from Figure 13, there may be produced in the metal a flat-bottomcountersink lllll, having a vertical wall I0! and a perfectly flat bottom I02, free of holes or depressions, the work remaining rigid on table l9 throughout the entire operation.

By the use of this mechanism, the time for make ready has been materially reduced over present methods, but mainly the period for completing the operation has been reduced by hours. Furthermore the mechanism may bequickly adjusted for operating on different types of metals or alloys by the selection of a single pin 9| if the material is hard, or two or more of the pins according to the softer characteristics of the material.

I claim:

1. A flat-bottom countersinking attachment for milling machines and the like including a spindle having a tool receiving chuck and a stationary part spaced laterally of the axis of the chuck; a head including a shank for said chuck, a tool carrier supported by said head, reciprocable transversely of the axis of said shank, a countersink cutter supported by said carrier extending laterally of its axis of movement, a screw for reciprocating said tool carrier, a toothed wheel on said screw located laterally of said head to rotate said screw and to bodily travel in a zone encircling said head as the spindle rotates, and an actuating device for said screw including an arm normally located in a plane parallel to said zone and loosely mounted on said shank to move longitudinally thereof, a rod secured to said arm and engaging said stationary part of the machine to arrest rotation of the arm with said shank, and one or more pins carried by said arm and normally projecting in the said zone to move said toothed wheel step-by-step as the head rotates.

2. A flat-bottom countersinking tool comprising a head including a top plate, a shank extending from the upper face thereof, an elongate guide block detachably secured to the lower face of said plate, provided with a slot of inverted T-shaped icross'section extending longitudinally of the block and transversely of the axis of said shank and a combined shaft receiving and thrust bearing member at one end of the slot co-axial with the upperportion of said slot; a tool carrier including an elongate body part guided and reciprocable in the lower portion of said slot and an upstanding block on said body portion, intermediate its ends, providedwith a screw threaded bore co-axial with said bearing member, and

movable in the upper portion-of said slot, and l a feed screw for said carrier provided with a shaft portion in said bearing member, a flange engaging said thrust receiving portion of the bearing member, and a screw threaded portion extending thru said bore.

3. A flat-bottom countersinking tool comprising a head including a top plate, a shank extending from the upper face thereof, a guide block detachably secured to the lower face of said plate, provided with a slot of inverted T-shaped cross section extending transversely of the axis of said shank and a combined shaft receiving and thrust bearing member at one end of the slot co-axial with the upper 'portion of said slot; a tool carrier including an elongate body part guided and reciprocable in the lower portion of said slot and an upstanding block provided with a screw threaded bore co-axial with said bearing member, and movable in the upper portion of said slot; a feed screw for said carrier provided with a shaft portion in said bearing member, a flange engaging the thrust receiving portion of the bearing member and a screw threaded portion extending thru said bore; and, spaced plates detachably carried by the bottom of said guide block, extending longitudinally of the lower portion of the slot and engaging the lower portion of said body part of the tool carrier.

4. In a countersinking tool, a carrier including an elongate body portion provided with a lon- 'gitudinally extending slot open to the top and bottom thereof, a set screw extending thru one end of said body portion, into said slot, a cutter including a work engaging portion and a shank portion received in said slot, and a substantially Z-shaped filler pieceand brace for the cutter disposed with its upper portion in said slot engaging the top of the cutter shank, its intermediate portion extending into and below said slot and engaging the cutter shank laterally, and its lower portion engaging the under side of the 'body portion of said carrier to limit upward PETER SHELBY. 

